1. Field of the Invention
The present invention relates to a control apparatus of a rotating electrical machine, such as an in-vehicle motor generator installed to a vehicle.
2. Background Art
Generally, a synchronous machine, such as a motor generator installed to a vehicle, is controlled by controlling a current flown to an armature winding of the synchronous machine on the basis of a position of a magnetic pole of a rotor detected by a magnetic pole position sensor, such as a synchro resolver. However, the synchronous machine has a problem that a desired torque cannot be obtained when there is displacement between a detection value of a position of the magnetic pole and an actual position of the magnetic pole due to an attachment error or misalignment of the magnetic pole position sensor.
To solve this problem, a control apparatus of a synchronous machine in the related art disclosed, for example, in Patent Document 1, is configured as follows. That is, inertia of a system and a load torque are preliminarily examined, and when a load torque of a synchronous machine is sufficiently small, a d-axis current and a q-axis current with which a torque of the synchronous machine becomes 0 are provided to an armature winding. On the basis of a variance of a rotating speed, a load torque, and inertia of the system at this point, an amount of displacement between a position of the magnetic pole detected by the magnetic pole position sensor and an actual position of the magnetic pole is found. According to the amount of displacement thus found, the detection position of the magnetic pole detected by the magnetic pole position sensor is corrected.
Also, a control apparatus of a synchronous machine in the related art disclosed in Patent Document 2 is configured as follows. That is, a permanent-magnet synchronous machine is driven by an inverter and a switching unit is provided between the inverter and the synchronous machine. The switching unit is opened after power is supplied to detect an inductive voltage waveform of the synchronous machine. The inductive voltage waveform thus detected is compared with an output signal of a magnetic pole position sensor that measures a rotating angle of the synchronous machine. An output error of the magnetic pole position sensor is found on the basis of a phase difference between the inductive voltage waveform and the output signal. An output signal of the magnetic pole position sensor is corrected according to the error thus found.
Patent Document 1: JP-A-2007-318894
Patent Document 2: JP-A-9-47066
In the case of the control apparatus of a synchronous machine in the related art disclosed in Patent Document 1, a load torque of the synchronous machine is used for the control. Hence, it is necessary to know a load torque of the synchronous machine that varies with a running condition of the vehicle by measuring the load torque in advance. Also, in a case where it is difficult to know an exact torque because the load torque varies, detection accuracy of an amount of displacement described above is deteriorated. Further, with the control apparatus of a synchronous machine in the related art disclosed in Patent Document 1, in a case where a position of the magnetic pole is detected in a region where a torque of the synchronous machine is small, influences of the load torque on a torque of the synchronous machine becomes considerable and detection accuracy of an amount of displacement described above is deteriorated in some cases due to a variation of the load torque.
Also, with the control apparatus of a synchronous machine in the related art disclosed in Patent Document 2, in order to detect a phase difference at the magnetic pole position sensor, it is necessary to provide a mode to measure an inductive voltage of the synchronous machine by opening the switching unit.